Built-up structural element



March 1950 I H. c. FISCHER ETAL BUILT-UP STRUCTURAL ELEMENT Filed May 3, 1946 IIIIII/I IIIII INVENTORS HERBERT C. FISCHER BY A ma/v HW./-//55//vs ATTORNEY Patented Mar. 21, 1950 QFFKQE BUILT-UP STRUCTURAL ELEMENT Herbert G. Fischer, Wellesley Hills, and Allan H. W. Higgins, Boston, Mass.

Application May 3, 1946, Serial No. 667,168

(El. i89-37) 2 Claims. 1

The present invention relates to built-up structural building elements and more particularly to an open-web beam or column which is so constructed as to permit attachment of collateral building members thereto by driven fasteners.

The invention has as an object to provide a low cost, light-weight structural element capable of receiving and holding driven fasteners. A further object of the invention is to provide a built-up structural element of the character referred to which provides a plurality of lines of nailing without the use of separate detachable nailing strips.

In accordance with the invention, a structural element is built-up by welding together, or otherwise suitably fastening, several separately formed Structural shapes of such a character that they may be manufactured inexpensively in continuous lengths by cold rolling or other simple procedure. Some of the component parts are so shaped during their fabrication as to provide means for receiving and holding driven fasteners of the nature of nails or screws. The built-up member includes two spaced chords which may be in tension or compression when the element is under load, and a stiffening web interconnecting the two chords. In a preferred arrangement the web is an open web and is secured to the chords at spaced points by electric welding.

The invention will be better understood from the following detailed description of a preferred embodiment and from the accompanying drawing referred to therein, in which:

Fig. l is a perspective view of the complete structural element;

Fig, 2 is a transverse sectional View of the upper chord of the structural element;

Fig. 3 is a side elevation of the upper chord, partly broken away to show details of construction, and

Fig. 4 is a fragmentary transverse section similar to Fig. 2 but showing a modification.

Referring to Fig. 1, the assembled structural element comprises an upper chord, indicated generally at 2, a lower chord t, and an intervening web 6 holding the two chords in spaced relationship and serving to stiffen the member against deflection under transverse stresses in the usual manner. The upper and lower chords are preferably identical in construction; each comprises a one-piece, shaped member of uniform cross-section throughout its length.

The built-up structural element of the present invention lends itself particularly to fabrication from steel of the kind commonly used in the outer walls E iand it.

manufacture of structural shapes for building construction, and the invention will be disclosed with particular reference to this material, although it will be understood that it is not intended thereby to exclude other suitable materials, such as plastics, for example. The steel shape forming the upper and lower chords is most conveniently formed by cold rolling a long length and then severing this length into separate members of the lengths desired. As shown particularly in Fig. 2, the chord member comprises a central portion 8 which is relatively fiat on both of its opposed upper and lower surfaces. At each side of the central portion 8 depending fastener-holding projections 10 and ii are provided by bending the strip stock from which the chord member is formed. Each of the projections l0 and 52 includes an inner wall is, extending approximately at right angles to the flat surfaces of the central portion 8, and an outer wall H5 spaced slightly from the inner wall it and lying generally parallel to it. The walls M and M are connected at their lower ends by a tubular portion 5% continuous with the inner and At the upper end of the outer wall l t the metal is bent outwardly to form a projection 20 lying generally in the plane of the central portion 8. The projection 20 is preferably relatively narrow and may have a width approximately of the order of onehalf the width of the central portion 8.

It will be observed that the one-piece chord member is so shaped as to provide a symmetrical distribution of metal about the vertical plane passing through the web. The fastener-holding projections l0 and I2 serve to stiffen the chord against buckling as well as to receive and hold fasteners.

Both of the walls M and it in each of the projections it and t2 are deformed to provide a series of spaced ribs 22 which are struck inwardly from the metal, that is, they project from the inner faces of the walls ill and It. The outside surfaces of the walls i l and it contain depressions 2 corresponding in shape to the ribs 22, resulting from the fact that the ribs 22 are formed by displacing the metal of the wall inwardly from the general plane of the wall. In the embodiment shown the ribs 22 in wall It are opposed to the ribs in wall it, that is, each rib in wall M is directly opposite a rib in wall I6. The ribs 22 taper upwardly to relatively sharp points 26 and are curved transversely of their length, as can be seen to best advantage in Figure 3.

Driven fasteners, such as the nail 30, to be received and held in the projections l0 and I2 are driven downwardly between the walls l4 and I6. If a nail happens to approach the element directly over a rib, the entering point of the nail will be deflected sidewise by the sharp point 26 of the rib and caused to enter the void between the rib and an adjacent rib. As the nail 30 moves downwardly it is constrained to follow the curvature of the ribs and is thus bent and securely held by the structural element. Should a nail be longer than the length of the ribs it will be received in the tubular portion i8 and its end clinched by the bottom of the portion [8 as shown at 32 in Fig. 3.

In the modification of Fig. 4, the portions 34 and 36 of the walls I4 and I6 lying between the points 26 of the ribs and the upper surfaces of the central portion 8 and the projection 20, are flared outwardly in the direction of the central portion. This flare provides an area for the reception of fasteners which is wider transversely of the structural element than is the case when the walls ill and iii are disposed as shown in Fig. 2. Thus, a nail which enters the fastener somewhat off the center line of the fastenerholding projection is deflected by the wall 3d or the wall 36 so that it is forced to enter one of the voids between the ribs 22.

The web connecting the two chord members 3 may be a flat metal sheet suitably secured to the under-surface of the central portion 8 of each chord. Preferably, however, in the interest of reduction in the cost and weight of the structural element, the web is of an open construction. The web (3 shown in Fig. 1 comprises a length of bar stock which is bent at spaced points to provide a plurality of struts 38 extending between the two chord members 2 and 4 at an inclination to both. The struts 38 in the illustrative embodiment are secured to the inside faces of the central portions 8 of the chord members 2 and t at the panel points 42 by spots of weld 44. At the end of the structural member, the bar forming the web may be bent to extend perpendicularly to the webs as indicated at 4B. When the structural element is to be used as a joist, it may be preferable to bend the lower chord member upwardly at the ends of the element to provide a bearing area at each end of the joist which is of less depth than the depth of the principal length of the element.

The built-up structural member of the present invention lends itself to use as a beam for such applications as joists, rafters, and the like, and also may be employed as a column. When employed as a joist it is not necessary to use the wooden sleepers ordinarily required when structural steel joists are employed, since the flooring or sub-flooring may be placed directly on the flat surface provided by the central portion 3 and the projection 20 and nailed down by nails which enter the fastener-holding projections l0 and I2.

The foregoing detailed description of an embodiment of the invention is made by way of illustration and not of limitation. Various changes may be made in the details of construction of the element without departure from the spirit of the invention as defined in the fo1- lowing claims.

We claim:

1. A builtup structural element comprising upper and lower chords, and a stiffening web connecting said chords, said chords each consisting of a one-piece elongated member constituting the entire stress-carrying element of the chord and having a central portion presenting on one face thereof a flat surface forming an outer surface of the chord and having the opposite face thereof connected to said web, and fastener-holding projections at each side of and r integral with said central portion extending from said central portion in the same direction as said web and having opposed walls spaced for the reception of driven fasteners, a plurality of opposed spaced ribs on each of said walls projecting above the surfaces of the walls and extending generally perpendicularly to said flat surface, said walls merging at their ends remote from said central portion into a curved wall connecting both walls of internal diameter greater than the spaces between the inner surfaces of said walls, whereby the space inside said curved wall can accommodate a plurality of driven fasteners at the same point.

2. A built-up structural element comprising upper and lower chords, and a stiffening web connecting said chords, said chords each consisting of a one-piece elongated member constituting the entire stress-carrying element of the chord and having a central portion presenting on one face thereof a flat surface forming an outer surface of the chord and having the 0pposite face thereof connected to said web, and fastener holding projections at each side of and integral with said central portion extending from said central portion in the same direction as said web and having opposed walls spaced for the reception of driven fasteners, a plurality of opposed spaced ribs on each of said walls projecting above the surface of the walls, extending generally perpendicularly to said flat surface, and terminating short of said central portion, a part of said walls between the central portion and said ribs flaring outwardly from said ribs, said walls merging at their ends remote from said central portion into a curved wall connecting both walls of internal diameter greater than the spaces between the inner surface of said walls, whereby the space inside said curved wall can accommodate a plurality of driven fasteners at the same point.

HERBERT C. FISCHER. ALLAN H. W. HIGGJNS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,804,452 Barton May 12, 1931 2,062,843 Strand Dec. 1, 1936 2,112,480 Coddlngton Mar. 29, 1938 

